Marvel of Peru is a plant that lives up to its name, even though it rarely, if ever, appears on garden center pallets. Practical gardeners call it”four o’clock.” Botanists, starting with Linnaeus, the great eighteenth century father of binomial nomenclature, refer to it with a Latin superlative — Mirabilis jalopa.
Whatever you call it, the common four o’clock looks a bit like its relative, the equally common petunia. Each flower features five broad petals, fused into a long trumpet. Blooming repeatedly during the growing season in shades of white, yellow, pink, red, purple, orange and peach, four o’clocks are also available in bi-colored varieties that feature vibrantly striped, splashed or marbled petals. The plants grow up to two feet tall and wide, with medium green, vaguely heart-shaped leaves. Native to Peru, Central America and Mexico, four o’clocks are not hardy in cold winter climates, so most people treat them as annuals.
Some seed vendors and horticultural writers refer to four o’clocks as “commuter plants,” because the flower buds open late in the day, just as commuters return home from work. Tradition wisdom holds that this trait is triggered by declining daylight, but researchers think the delayed opening is actually a response to the gradual decrease in temperatures that normally happens in the late afternoon. The ancient Aztecs may not have been commuters, but they apparently appreciated four o’clocks and may even have selected particularly desirable varieties for cultivation. Spanish colonists sent four o’clocks back to Spain, where they caught on. As with so many things horticultural, the plants made their way to England, where they also became favorites. Thomas Jefferson marveled at marvel of Peru when he grew the related Mirabilis longiflorum at Monticello. Jefferson’s white-flowered species boasted trumpets even longer than those of the jalapa species. A little later, in the mid to late nineteenth century, Victorians took to the versatile, colorful plants, using them in bedding schemes.
Beauty is only one chapter of the four o’clock story. Like many old-fashioned garden plants, the flowers are fragrant, with a sweet citrusy scent. This is as alluring to hummingbirds and moths as it is to humans and makes four o’clocks a good choice for beds or large containers that are near paths or seating areas.
The best way to start the plants is from seed, which can be sown directly in the garden after all danger of frost has passed. Sun to light shade is best for optimal flowering. If you are very ambitious, you can opt to start the seeds inside, six to eight weeks before the last frost date for your area. Once the seeds establish themselves and grow into vigorous plants, tuberous roots develop below the soil. Thrifty souls in cold winter climates can dig these tubers in the fall and store them, like cannas or dahlias. Replanted the following spring, they will bloom quicker than the same varieties started from seed. In climates where four o’clocks are perennial, the tubers can reach up to forty pounds. If you can imagine a forty pound potato or parsnip, you can imagine what a forty pound four o’clock tuber might look like. Not every garden plant can double as a strength training accessory.
As with some other beautiful, exceptionally vigorous plants, four o’clocks come with a caveat. When happy, they are rampant self-seeders, which may be alarming to neat and tidy gardeners. However, unwanted seedlings are easy to remove, as they don’t produce those forty pound tubers in their first few months of existence. In some places, especially where the plants are perennial, they have been reported as invasive. Like other nightshade-type plants, the parts are poisonous, so caution should be used around small children and animals.
Cottage gardeners relish any plant that self-seeds, so four o’clocks are naturals for that application. They will fit in happily as single specimens wherever a bit of color is needed and can be cut back after each flush of bloom to stimulate rebloom and keep the plants in a compact, bushy configuration. Some imaginative gardeners even line up their four o’clocks and use them as low, flowering hedges.
When I think of the many virtues of the marvel of Peru, I wonder why I haven’t marveled at it more myself over the years. Following my long-held garden philosophy– “If it worked for the Aztecs, it will work in New Jersey”—I am going to invest in some for next summer’s garden.
Many seed vendors sell Mirabilis jalopa and Mirabilis longiflorum seeds, both online and in retail stores. You can find a good selection at Select Seeds, 180 Stickney Hill Rd., Union, CT 06076, (800) 684-0395; www.selectseeds.com. Free catalog.